diff --git a/platform/lang-impl/src/com/intellij/psi/formatter/common/NewLineBlocksIterator.java b/platform/lang-impl/src/com/intellij/psi/formatter/common/NewLineBlocksIterator.java
index 9ca8ddcf03c7..5a170dfa0c0c 100644
--- a/platform/lang-impl/src/com/intellij/psi/formatter/common/NewLineBlocksIterator.java
+++ b/platform/lang-impl/src/com/intellij/psi/formatter/common/NewLineBlocksIterator.java
@@ -102,5 +102,6 @@ public class NewLineBlocksIterator implements Iterator<Block> {
 
   @Override
   public void remove() {
+    throw new UnsupportedOperationException();
   }
 }